Conversion of hydrocarbon oils



Aug. 16, 1938. A. ENGELSTEIN CONVERSION OF HYDRO C ARBON OILS Filed Oct. 8, 1934 INVENTOR Patented Aug. 16, 1938 iiNi'iED STATES PATENT OFFIQE CONVERSION OF HYDROGARBON OILS Alvin Engelstein, Chicago,

versal Oil Products Company,

111., assignor to Uni- Chicago, 111., a

2 Claims.

This invention particularly refers to an improved process for the conversion of hydrocarbon oils which is particularly well adapted to the treatment of relatively high-boiling oils or oils of relatively wide boiling range.

It is one of the primary objects of the present invention to provide an improved process for the conversion of relatively high-boiling oils such as fuel oil or residual oils, generally, as well as oils of relatively wide boiling range such as crude petroleum, topped crude and the like, which contain an appreciable quantity of relatively high-boiling components, wherein heavy components of the charging stock unsuitable for conversion under conditions as severe as those which give the best results for the treatment of its lower boiling components are removed from the charging stock and subjected to more suitable milder conversion conditions within the same system. In the present invention this is accomplished in a single unified system of simple form, segregation of the charging stock into selected low-boiling and high-boiling fractions being accomplished by direct contact and heat exchange with vaporous conversion products of the process, prior to fractionation of the latter for the formation of reflux condensate, which is returned to the heating coil of the system for further conversion, and subsequent to partial cooling of the vaporous conversion products by their indirect contact and heat exchange with said reflux condensate.

In one specific embodiment, the invention comprises subjecting an oil to conversion conditions of elevated temperature and superatmospheric pressure in a heating coil and communicating reaction chamber, withdrawing vaporous and liquid conversion products from the reaction chamber, sub ecting vaporous conversion products of the process, following partial condensation and cooling thereof, as will be later more fully described, to fractionation for the formation of reflux condensate comprising their insufficiently converted components suitable for further conversion in said heating coil, passing a regulated portion or all of said reflux condensate in indirect heat exchange with said vaporous conversion products, prior to said fractionation thereof, and then supplying the reflux condensate to the heating coil for further conversion, introducing hydrocarbon oil charging stock for the process into direct contact with said vaporous. conversion products of the process subsequent to said heat exchange with the reflux condensate and prior to said fractionation, whereby to further cool and remove from the vapors selected high-boiling components and to heat the charging stock whereby its low-boiling components are subjected to vaporization and fractionated together with said vaporous conversion products, 5 returning high-boiling components of the charging stock remaining unvaporized by said contact with the vaporous conversion products and condensate removed from the vaporous conversion products by said direct contact with the charg- 10 ing stock and said indirect heat exchange with the reflux condensate to an intermediate point in the heating coil whereby said condensate and high-boiling fractions of the charging stock are subjected to less severe conversion conditions 15 than the reflux condensate.

It is also Within the scope of the present invention instead of supplying a condensate, comprising the high-boi1ing components of the vaporous conversion products, and the high-boiling 20 fractions of the charging stock to an intermediate point in the heating coil to commingle the same, all or in part, with the stream of hot conversion products passing from the heating coil to the reaction chamber or to introduce the same 25 into the reaction chamber at any desired point in this zone. This provision is of particular advantage in case it is desired to subject said condensate to somewhat milder conversion than that obtainable by passing the same through the 30 final stages of the heating coil. In case still less or substantially no conversion of the condensate is desired it may be supplied to the vaporizing chamber or commingled with the stream of products passing from the reaction chamber to the 35 vaporizing chamber, in which case a major portion of said condensate will commingle in the vaporizing chamber with the residual liquid conversion products in this zone to form the final residual liquid product of the process.

The accompanying diagrammatic drawing and following description thereof is included for the purpose of illustrating one specific form of apparatus in which the invention may be carried out. It will be understood, of course, that the invention is not limited to the specific form of apparatus illustrated.

Referring to the drawing, heating coil I is located in a furnace 2 of any suitable form which supplies the required heat to the oil passing through the heating coil to subject the same to the desired conversion temperature in this zone preferably at a substantially superatmospheric pressure. Hot conversion products are discharged from heating coil I through line 3 and valve 4 into reaction chamber 5.

Chamber 5 is also preferably maintained at a substantial superatmospheric pressure which may be substantially the same or somewhat lower than that employed at the outlet from the heating coil and, although not indicated in the drawing, the reaction chamber is preferably insulated to prevent the excessive loss of heat therefrom by radiation so that the materials supplied to this zone, and particularly their vaporous components, may be subjected to additional conversion therein.

Both vaporous and liquid conversion products are withdrawn, in the case here illustrated, in commingled state from the lower portion of chamber 5 and are supplied through line 6 and valve to vaporizing chamber 8. It is, of course, also within the scope of the present invention to separately remove all or a regulated portion of the vaporous conversion products from any desired point in chamber 5 above the point of removal of the liquid conversion products, in which case the vaporous products may be supplied, all or in part, to chamber 8 at any desired point in this zone or to heat exchanger [3.

vaporizing chamber 8 is preferably operated at a substantially reduced pressure relative to that employed in chamber 5 whereby further vaporization of the liquid supplied to this zone is accomplished. Residual liquid remaining unvaporizedin chamber 8 may be Withdrawn from the lower portion thereof through line 9 and valve ill to cooling and storage or to any desired further treatment. Vaporous products are removed from the upper portion of chamber 8 through line H and valve 12 and supplied to heat exchanger l3 wherein they are subjected to partial cooling by indirect contact with reflux condensate produced within the system, as will be later more fully described.

The vaporous conversion products remaining uncondensed in heat exchanger l3 are directed therefrom through line I4 and valve 15 to column 16 wherein they are subjected to additional cooling and condensation by direct contact with hydrocarbon oil charging stock for the process supplied thereto, as will be later more fully described. Vaporous conversion products still remaining uncondensed are removed from the upper portion of column I6, together with the components of the charging stock which are vaporized in this zone, and the commingled vaporous materials pass through line I! and valve l8 to be subjected to fractionation in fractionator l 9.

Components of the vapors supplied to fractionator l9 boiling above the range of the desired final light distillate product of the process are condensed in this zone as reflux condensate. The reflux condensate is withdrawn from. the lower portion of fractionator 19 through line 20 and valve 2| to pump 22 by means of which it is fed through line 23, valve 24 and line 25 and may be directed, all or in part, through valve 26 in line 25, through heat exchanger l3, in indirect contact with the vaporous conversion products supplied to this zone, as previously described, the reflux condensate being directed thence through line 25, valve 26 and line 28 to heating coil l for further conversion. When desired, a regulated portion of the reflux condensate may bypass heat exchanger 13 by means of valve 29 in line 28.

Fractionated vapors of the desired end-boiling point are removed, together with uncondensable gas produced within the process, from the upper portion of the fractionator through line 30 and valve 3| and are subjected to condensation and cooling in condenser 32. The resulting distillate and gas passes through line 33 and valve 34 to collection and separation in receiver 35. Uncon-. densable gas may be released from the receiver through line 36 and valve 37. Distillate may be withdrawn from receiver 35 through line 38 and valve 39 to storage or to any desired further treatment. When desired, a regulated portion of the distillate collected in receiver 35 may be recirculated, by well known means, not shown in the drawing, to the upper portion of fractionator 19 to serve as a cooling and refluxing medium in this zone to assist fractionation of the vapors and to maintain the desired vapor outlet temperature from. the fractionator.

Hydrocarbon oil charging stock for the process is supplied through line 40 and valve 4| to pump 42 by means of which it is fed through line 43 and may be directed, all or in part, through line 44 and valve 45 to column l6 wherein it is preheated and subjected to vaporization by direct contact with the vaporous conversion products in this zone, serving to partially cool said vaporous products and eflect condensation oi their heavy components. It is also within the scope of the present invention, when desired, to direct regulated portions of the charging stock through line 46 and valve 41 to fractionator 19 to serve as a refluxing and cooling medium in this zone and be thereby heated and subjected to vaporization or regulated portion of the chargthe stock may, when desired, be directed from line 44 through line 48 and valve 49 into line 25 to commingle therein with the reflux condensate from fractionator l9 and be subjected to further treatment therewith, in the manner already described.

Condensate removed from the vaporous conversion products in heat exchanger l3 by their indirect contact with reflux condensate or commingled reflux condensate and charging stock in this zone is withdrawn from the lower portion thereof through line 50 and valve 5| passing thence, in the case here illustrated, through line 52 to pump 53. Condensate comprising additional quantities of the high-boiling components of the vaporous conversion products formed in column I6 is removed together with high-boiling components of the charging stock supplied to this zone which remain unvaporized therein through line 54 and valve 55 and, in the case here illustrated, is also directed through line 52 to pump 53. The relatively heavy oils thus supplied to pump 53 are fed therefrom through line 56 and may be supplied, all or in part, through line 51 and valve 58 to a suitable intermediate point in heating coil i wherein the relatively heavy oil commingles with the stream of lower boiling oils, or the conversion products resulting therefrom,

"passing through the heating coil to be subjected therewith to conversion in of this zone.

The temperature employed in the final stages of heating coil I, following the introduction of said relatively high-boiling oils, may be substantially the same, somewhat higher, or somewhat lower than the temperature to which the relatively low-boiling oils are heated in the preceding portion of the heating coil. In any case, however, the conversion conditions to which said relatively high-boiling oils are subjected in the the remaining portion heating coil are less severe than those to which 75 the relatively low-boiling oils are subjected in this zone, due to the shorter time factor employed for the relatively high-boiling oilsand to the somewhat lower pressure necessitated in the final stages of the heating coil, due to the friction through this zone. Preferably, although not illustrated in the drawing, the arrangement of heating coil l within furnace 2 is such thata considerable degree of independent control is exerted over the heating conditions about the final stages of the heating coil, subsequent to the introduction of said relatively high-boiling oils, relative to the heating conditions in the preceding portion of the coil. Means for accomplishing this are now well known in the art and, for the sake of simplicity, are not here illustrated.

In case it is desired to subject the relatively high-boiling oils from heat exchanger l3 and column IE to somewhat milder conversion conditions than those obtainable by introducing the same to an intermediate point in heating coil I, provision is made in the present invention for commingling the same with the stream of heated products passing from the heating coil to the reaction chamber, subsequent to their discharge from the heating coil, or they may be separately supplied to the reaction chamber at any desired point in this zone. Valve 59 in line 56 is illustrative of the means which may be employed for introducing the relatively high-boiling oils into transfer line 3 to commingle with the stream of heated products from heating coil and be directed therewith to chamber 5 and line 60 controlled by valve Si is illustrative of means for separately supplying the relatively high-boiling oils to the reaction chamber.

It is also within the scope of the present invention to supply all or a regulated portion of the "high-boiling oils from heat exchanger l3 and column IE to vaporizing chamber 8 at any desired point in this zone. This may be accomplished by ccmmingling the same with the stream of products in line 6 passing from chamber 5 to chamber 8, for example, by means of line 62 and valve 63, or the relatively high-boiling oils may be separately supplied to the vaporizing chamber at any desired point in this zone by well known means, not illustrated. In case this method of operation is employed, little or substantially no conversion of the relatively high-boiling oils will be accomplished and their components remaining unvaporized in chamber 8 will commingle with the residual liquid conversion products withdrawn from this zone, as previously described, the commingled materials forming the such as illustrated and above described may be approximately as follows: A conversion temperature ranging, for xarnple, from 800 to 950 F, may be employed at the outlet from the heating coil preferably with a substantial superatmo- 55 spheric pressure measured at this point in the system of from 100 to 500 pounds, or more, per square inch. The conversion temperature in the heating coil measured at a point just prior to the point of introduction of the relatively high- 70 boiling oils, when this method of operation is employed, may range, for example, from 850 to 1000" F., or thereabouts. A substantial superatmospheric pressure which may be either substantially the same or somewhat lower than 75 that employed at the outlet from the heating coil is utilized. in the reaction chamber and the vaporizing chamber is preferably operated at a substantially reduced pressure relative to that employed in the reaction chamber ranging, for example, from 100 pounds, or thereabouts, per square inch, down to substantially atmospheric pressure. The portions of the system succeed ing the vaporizing chamber may utilize pressures substantially the same or somewhat lower than the pressure employed in the vaporizing chamber. As a specific example of the operation of the process of the present invention as it may be accomplished in an apparatus such as illustrated and above described, utilizing as charging stock a Kansas crude oil of about 20 A. P. I. gravity containing no appreciable quantity of materials within the boiling range of gasoline, high-boiling components of the vaporous conversion products and of the charging stock, recovered, in the manner illustrated and above described, containing no substantial quantity of materials boiling below 650 F., are supplied to an intermediate point in the heating coil. The lower boiling components of the charging stock and the reflux condensate are subjected in that portion of the heating coil preceding the introduction of the relatively high-boiling oils to a temperature of approximately 950 F. The temperature at the outlet from the heating coil is approximately 900 F. A superatmospheric pressure of approximate ly 350 pounds per square inch is employed at the outlet from the heating coil and substantially the same pressure is utilized in the succeeding reaction chamber. The vaporizing chamber is operated at a reduced pressure of approximately 50 pounds per square inch which is substantially equalized in the succeeding portions of the system. This operation will produce, per barrel of charging stock, approximately 48 percent of motor fuel having an antiknock value equivalent to an octane number of approximately '70 and about 42 percent of premium fuel oil, the remainder being chargeable, principally, to uncondensable gas and loss.

I claim as my invention:

1. A hydrocarbon oil conversion process which comprises heating reflux condensate, formed as hereinafter set forth, to cracking temperature under pressure while flowing in a restricted stream through a heating coil, subsequently separating the resultant heated products into vapors and residue, partially condensing the vapors by indirect heat exchange with said reflux condensate prior to introduction of the latter to the heating coil and by direct contact with relatively heavy charging oil for the process, thereby preheating the reflux condensate and partially distilling the charging oil, combining condensate formed by said indirect heat exchange with the unvaporized portion of the charging oil and introducing the resultant mixture to said coil at an intermediate point in the flow of the reflux condensate therethrough, fractionating the va pors uncondensed by said partial condensation to separate insufficiently cracked fractions thereof, passing such separated insufliciently cracked fractions in indirect heat exchange with the firstnamed vapors and thence to the heating coil as said reflux condensate, and finally condensing the fractionated vapors.

2. A hydrocarbon oil conversion process which comprises heating reflux condensate, formed as hereinafter set forth, to cracking temperature under pressure while flowing in a restricted stream through a heating coil, subsequently separating the resultant heated products into vapors and residue, passing the vapors first through an indirect heat exchange zone and then into a direct heat exchange zone, contacting the vapors in the last-named zone with relatively heavy charging oil for the process, thereby partially distilling the charging oil and condensing heavier portions of the vapors, fractionating the uncondensed vapors from the last-named zone to separate insufiiciently cracked fractions thereof, passing such separated insufiiciently cracked ALVIN ENGELSTEIN. 

